/*
 * Copyright (c) 2010-2018 Nathan Rajlich
 *
 *  Permission is hereby granted, free of charge, to any person
 *  obtaining a copy of this software and associated documentation
 *  files (the "Software"), to deal in the Software without
 *  restriction, including without limitation the rights to use,
 *  copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the
 *  Software is furnished to do so, subject to the following
 *  conditions:
 *
 *  The above copyright notice and this permission notice shall be
 *  included in all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *  OTHER DEALINGS IN THE SOFTWARE.
 */

package com.alipay.api.java_websocket;

import com.alipay.api.java_websocket.drafts.Draft;
import com.alipay.api.java_websocket.exceptions.InvalidDataException;
import com.alipay.api.java_websocket.framing.CloseFrame;
import com.alipay.api.java_websocket.framing.Framedata;
import com.alipay.api.java_websocket.handshake.ClientHandshake;
import com.alipay.api.java_websocket.handshake.Handshakedata;
import com.alipay.api.java_websocket.handshake.ServerHandshake;
import com.alipay.api.java_websocket.handshake.ServerHandshakeBuilder;

import java.net.InetSocketAddress;
import java.nio.ByteBuffer;

/**
 * Implemented by <tt>WebSocketClient</tt> and <tt>WebSocketServer</tt>. The methods within are called by <tt>WebSocket</tt>. Almost every
 * method takes a first parameter conn which represents the source of the respective event.
 */
public interface WebSocketListener {

    /**
     * Called on the server side when the socket connection is first established, and the WebSocket handshake has been received. This method
     * allows to deny connections based on the received handshake.<br> By default this method only requires protocol compliance.
     *
     * @param conn    The WebSocket related to this event
     * @param draft   The protocol draft the client uses to connect
     * @param request The opening http message send by the client. Can be used to access additional fields like cookies.
     * @return Returns an incomplete handshake containing all optional fields
     * @throws InvalidDataException Throwing this exception will cause this handshake to be rejected
     */
    ServerHandshakeBuilder onWebsocketHandshakeReceivedAsServer(WebSocket conn, Draft draft, ClientHandshake request)
            throws InvalidDataException;

    /**
     * Called on the client side when the socket connection is first established, and the WebSocketImpl handshake response has been
     * received.
     *
     * @param conn     The WebSocket related to this event
     * @param request  The handshake initially send out to the server by this websocket.
     * @param response The handshake the server sent in response to the request.
     * @throws InvalidDataException Allows the client to reject the connection with the server in respect of its handshake response.
     */
    void onWebsocketHandshakeReceivedAsClient(WebSocket conn, ClientHandshake request, ServerHandshake response)
            throws InvalidDataException;

    /**
     * Called on the client side when the socket connection is first established, and the WebSocketImpl handshake has just been sent.
     *
     * @param conn    The WebSocket related to this event
     * @param request The handshake sent to the server by this websocket
     * @throws InvalidDataException Allows the client to stop the connection from progressing
     */
    void onWebsocketHandshakeSentAsClient(WebSocket conn, ClientHandshake request) throws InvalidDataException;

    /**
     * Called when an entire text frame has been received. Do whatever you want here...
     *
     * @param conn    The <tt>WebSocket</tt> instance this event is occurring on.
     * @param message The UTF-8 decoded message that was received.
     */
    void onWebsocketMessage(WebSocket conn, String message);

    /**
     * Called when an entire binary frame has been received. Do whatever you want here...
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occurring on.
     * @param blob The binary message that was received.
     */
    void onWebsocketMessage(WebSocket conn, ByteBuffer blob);

    /**
     * Called after <var>onHandshakeReceived</var> returns <var>true</var>. Indicates that a complete WebSocket connection has been
     * established, and we are ready to send/receive data.
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @param d    The handshake of the websocket instance
     */
    void onWebsocketOpen(WebSocket conn, Handshakedata d);

    /**
     * Called after <tt>WebSocket#close</tt> is explicity called, or when the other end of the WebSocket connection is closed.
     *
     * @param ws     The <tt>WebSocket</tt> instance this event is occuring on.
     * @param code   The codes can be looked up here: {@link CloseFrame}
     * @param reason Additional information string
     * @param remote Returns whether or not the closing of the connection was initiated by the remote host.
     */
    void onWebsocketClose(WebSocket ws, int code, String reason, boolean remote);

    /**
     * Called as soon as no further frames are accepted
     *
     * @param ws     The <tt>WebSocket</tt> instance this event is occuring on.
     * @param code   The codes can be looked up here: {@link CloseFrame}
     * @param reason Additional information string
     * @param remote Returns whether or not the closing of the connection was initiated by the remote host.
     */
    void onWebsocketClosing(WebSocket ws, int code, String reason, boolean remote);

    /**
     * send when this peer sends a close handshake
     *
     * @param ws     The <tt>WebSocket</tt> instance this event is occuring on.
     * @param code   The codes can be looked up here: {@link CloseFrame}
     * @param reason Additional information string
     */
    void onWebsocketCloseInitiated(WebSocket ws, int code, String reason);

    /**
     * Called if an exception worth noting occurred. If an error causes the connection to fail onClose will be called additionally
     * afterwards.
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @param ex   The exception that occurred. <br> Might be null if the exception is not related to any specific connection. For example
     *             if the server port could not be bound.
     */
    void onWebsocketError(WebSocket conn, Exception ex);

    /**
     * Called a ping frame has been received. This method must send a corresponding pong by itself.
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @param f    The ping frame. Control frames may contain payload.
     */
    void onWebsocketPing(WebSocket conn, Framedata f);

    /**
     * Called when a pong frame is received.
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @param f    The pong frame. Control frames may contain payload.
     **/
    void onWebsocketPong(WebSocket conn, Framedata f);

    /**
     * This method is used to inform the selector thread that there is data queued to be written to the socket.
     *
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     */
    void onWriteDemand(WebSocket conn);

    /**
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @return Returns the address of the endpoint this socket is bound to.
     * @see WebSocket#getLocalSocketAddress()
     */
    InetSocketAddress getLocalSocketAddress(WebSocket conn);

    /**
     * @param conn The <tt>WebSocket</tt> instance this event is occuring on.
     * @return Returns the address of the endpoint this socket is connected to, or{@code null} if it is unconnected.
     * @see WebSocket#getRemoteSocketAddress()
     */
    InetSocketAddress getRemoteSocketAddress(WebSocket conn);
}
